Gas Mask Filter Shelf Life
One gas mask filter – like all other filters – it has a limited shelf life and breakthrough time It is called . This means that the carbon granules are now cannot absorb a pollutant (toxic gas) time occurs. As a result, the user can no longer breathe clean filtered air.
One gas mask filter, It has a microporous structure made of carbon with a very large absorption surface in a small cartridge. Thanks to this technology, filters contain less carbon (220 to 230 mL), which reduces weight and breathing effort. Tables with theoretical shelf lives are available, but they should never be taken. Indeed, the shelf life of a gas filter depends on various factors.
Factors affecting gas filter shelf life
- gas concentration : Higher concentrations rapidly accumulate the pollutant in carbon, accelerating the elimination time.
- Filtered air flow or respiratory rate : theoretical shelf lives are determined based on an air flow of 30 liters per minute. A higher respiratory rate will reduce excretion time.
- Heat : If the operating temperature increases, the shelf life of the gas filter will decrease
- Relative humidity : VOC’ler High humidity will accelerate excretion time. The opposite effect occurs for some gases such as ammonia (nh3) or hydrogen sulfide (h2s).
- Shocks : Shocks in a breathing cartridge have harmful effects. Because they pack the granules, shocks will reduce their absorption power
Gas mask filter shelf life calculation
There is a formula for calculating the shelf life of a gas filter:
Shelf life = (1 000 000 x filter capacity*) / (respiration rate x gas concentration)
* Filter capacity depends on the manufacturer. Available on technical information pages.
Breakthrough time of gas mask filter
Gas filters for negative pressure breathing apparatus
Test preface: Gas masks (negative pressure) test gas concentrations were set at 1,000 ppm (0.1 vol%) for class 1 and 5,000 ppm (0.5 vol%) for class 2.
Spasciani DIN Rd40 filters Fits most EN 148-1 approved gas masks with 40 mm universal thread.
| Filter type | test gas | breakthrough time | |
|---|---|---|---|
| 1st Class | Class 2 | ||
| A | Cyclohexane (C6H12) | 70 dk | 35 min |
| B | Chlorine (Cl2) | 20 minutes | 20 minutes |
| B | Hydrogen sulfide (H2S) | 40 min | 40 min |
| B | Hydrogen cyanide (HCN) | 25 min | 25 min |
| E | Sulfur dioxide (SO2) | 20 minutes | 20 minutes |
| K | Ammonia (NH3) | 50 min | 40 min |
Gas filters for powered air-purifying respirators
Test preface: PAPR masks Test gas concentrations were set at 500 ppm (0.05 vol%) for class 1 and 1,000 ppm (0.1 vol%) for class 2.
| Filter type | test gas | breakthrough time | |
|---|---|---|---|
| 1st Class | Class 2 | ||
| A | Cyclohexane (C6H12) | 70 dk | 35 min |
| B | Chlorine (Cl2) | 20 minutes | 20 minutes |
| B | Hydrogen sulfide (H2S) | 40 min | 40 min |
| B | Hydrogen cyanide (HCN) | 25 min | 25 min |
| E | Sulfur dioxide (SO2) | 20 minutes | 20 minutes |
| K | Ammonia (NH3) | 50 min | 40 min |
Breakthrough times of special filters (AX and Hg-P3)
| Filter type | test gas | gas concentration | breakthrough time |
|---|---|---|---|
| AX | Isobutane (C4H10) | 2.500 ppm | 50 min |
| Hg-P3 | mercury vapor | 1.6 ml/mg | 100 hours |
